Squid issues using Satellite system

Ben Capili writes:
> I don't know if this is more a question on routing or on Squid but I'm at a
> loss for a solution, so I hope someone out there can help me.
>
> I'm using Squid 2.2 STABLE4 on a RH 6.1 box. We are trying to deploy an
> ISP-type system using an internet connection over satellite. The limitation
> with accessing the Internet over satellite is that it is uni-directional
> (downstream) from the satellite so therefore, HTTP requests have to be sent
> back up via a conventional dial-up modem.
>
> Here's the situation:
>
> A client dials out through their local ISP in order to access the Squid
> proxy. (The proxy, of course, has a static IP) The Squid box needs a
> default gateway in order to access the internet (let's say via a T1 line) to
> retrieve the data that was requested by the client. Now, in order to
> forward this data to the "satellite side", the Squid proxy has to be routed
> to a special gateway that can send this data over to the "satellite side" &
> not back through the conventional internet path, otherwise it would just be
> relayed back to the client via the modem (which would be much slower).
>
> So here's my question. Is there anything I can put in the squid.conf file
> to direct the internet data it has retrieved to a particular gateway/server?
> I know you can direct it to another proxy but what about just another
> gateway? I thought I could do it via the routing table but how would you be
> able to route all traffic to a particular server and also have a default
> gateway to access the internet to retrieve data from HTTP requests? By
> having a default gateway to access the internet, all traffic flows out
> through this gateway & not to the gateway I want it to. At least this is
> how I understand it. I hope someone with more routing expertise can help me
> understand this.

I've never done this before, but i've been reading some docs on
satellite connections, with a view to doing a similar thing. It
appears that what should happen is that the default route on the
internet for your dialup client actually points to the satellite
centre, and you use a ip tunnel on the dialup client to get packets
out through the modem back to the rest of the internet.
 
so, what happens, is that a request is generated on the client, it has
the source ip of the satellite connection on the packets. it is then
wrapped up in another ip packet (the tunneling bit) which travells out
through your modem to the other end of the tunnel, probably at your
isp or the satellite centre. Next the packet is decapsulated e.g. the
extra headers that were put on for it to travel through the tunnel are
removed. At this point the packet is out on the internet with the
source ip of the satellite connection and the destination of where
ever it was going. The packet travels to it's destination, and any
packets sent in return travel to the satelite centre and via satellite
to your client.

this way, your proxy machine would only need to set it's default route.

hope this makes sense, and if anyone can see a problem with this
explanation, please let me know why it won't work as i'm about to try
it myself once the satellite connection is installed.

HTH
Bart

>
> Please Help!! Thank you in advance.
>
> Sincerely,
>
Received on Thu Jun 15 2000 - 18:26:10 MDT